Altman R, et al. - This trial was formulated in order to gauge the efficacy and safety of repeated courses of intra-articular-hyaluronic acid (IA-HA) injection therapy in individuals with knee osteoarthritis (OA). Yielded data demonstrated the effectiveness and safety of repeated courses of IA-HA injections for knee OA. Maintenance and additional improvement were achieved in the pain reduction through repeat courses, with no increased safety risk.